Influence of Size of Hematite Powder on Its Reduction Kinetics by H_2 at Low Temperature

作     者：PANG Jian-ming GUO Pei-min ZHAO Pei CAO Chao-zhen ZHANG Dian-wei 

作者机构：The State Key Laboratory for Advanced Iron and Steel Processes and Materials Central Iron and Steel Research Institute Beijing 100081 China 

出 版 物：《Journal of Iron and Steel Research International》 (J. Iron Steel Res. Int.)

年 卷 期：2009年第16卷第5期

页      面：7-11页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 080601[工学-冶金物理化学] 

基　　金：Sponsored by National Natural Science Foundation of China(50474006) National Science and Technology Support Program for the 11th Five-Year Plan(2006BAE03A12,2006BAE03A05) 

主　　题：iron oxide low temperature reduction kinetics thermogravimetric analysis (TGA), reduction mechanism 

摘      要：The reduction kinetics and mechanisms of hematite ore with various particle sizes with hydrogen at low temperature were studied using the thermogravimetric analysis. At the same temperature, after the particle size of powder decreases from 107. 5μm to 2. 0 μm, the surface area of the powder and the contact area between the powder and gas increase, which makes the reduction process of hematite accelerate by about 8 times, and the apparent activation energy of the reduction reaction drops to 36.9 kJ/mol from 78. 3 kJ/mol because the activity of ore powder is improved by refining gradually. With the same reaction rate, the reaction temperature of 6.5 μm powder decreases by about 80 ℃ compared with that of 107. 5 μm powder. Thinner diffusion layer can also accelerate the reaction owing to powder refining. The higher the temperature, the greater is the peak of the reduction rate; at the same temperature, the greater the particle size, the smaller is the peak value of the reduction rate; both inner diffusion and interface chemical reaction play an important role in the whole reaction process.